1. Field of the Invention
This invention relates to a novel catalyst system for the polymerization of alpha-olefins, a novel titanium halide containing catalyst component used in said system, a process for producing said component and a process for the polymerization of alpha-olefins using such catalyst system.
2. Prior Art
The polymerization of alpha-olefins in the presence of a catalyst system comprising: (a) an organoaluminum containing component, and (b) a titanium halide containing component is well known in the art and the polymers produced utilizing such catalyst systems have found numerous uses. The resulting crystalline polymers have associated therewith, to a greater or lesser degree, a low molecular weight amorphous polymer. The production of polymers having a low concentration of such amorphous polymers results in a polymer having highly desirable properties. The production of highly stereoregular crystalline polymers is thus a desirable objective for a catalyst system and polymerization process.
It is also desirable that high amounts of polymer be produced per unit of time per unit of catalyst employed, i.e. the catalyst system have a high activity. Ideally, it is highly desirable to simultaneously improve the stereospecificity and activity of a catalyst system.
Various approaches to achieving the aforementioned objectives have been proposed in the art.
South African Pat. No. 78/1023 to Toyota et al. describes producing a titanium halide containing component by reacting a mechanically pulverized product of an organic acid ester and a halogen containing magnesium compound, with an active hydrogen containing organic compound in the absence of mechanical pulverization. The resulting reaction product is then reacted with an organometallic compound of a metal of Groups I to III of the Periodic Table in the absence of mechanical pulverization. The resulting solid reaction product is then washed with an inert organic solvent, and the resultant solid reacted with a titanium compound in the absence of mechanical pulverization. The resultant solids are then separated from the reaction system. This reference, however, does not teach reacting with an organic phosphite and requires an active hydrogen containing organic compound and an organometallic compound.
U.S. Pat. No. 4,143,223 to Toyota et al. describes reacting a mechanically co-pulverized solid component of, for example, magnesium chloride, an organic acid ester and an active hydrogen containing compound, e.g. phenol, with a tetravalent titanium compound, e.g. TiCl.sub.4. This reference does not teach reacting with an organic phosphite.
Japanese Tokkyo Koho 79 34,429 to Kuroda et al. (as reported in CA 92:129640n) polymerizes ethylene using a mixture of trialkylaluminum, alkylhaloaluminum, and a ball milled solid product of Mg halide, phosphite esters, Ti(IV) compounds and Ti(III) compounds. This titanium halide containing component is produced by a different process using different ingredients than the invention described herein.
U.S. Pat. No. 4,130,503 to Fodor describes a catalyst component comprising a magnesium chloride support, a titanium trichloride, an aluminum trichloride and an organic phosphite. Exemplary of such a component is an MgCl.sub.2 supported TiCl.sub.3.1/3AlCl.sub.3 plus triphenyl phosphite catalyst component. This reference, however, does not describe the use of an electron-donor compound or TiCl.sub.4 and generally relates to a different class of catalyst components with respect to the activity thereof.
U.S. Pat. No. 3,953,414 to Galli et al. describes the use of triphenyl phosphine and tri-isobutyl aluminum in conjunction with a titanium halide containing catalyst component prepared in a specific manner from MgCl.sub.2 and TiCl.sub.4. This reference does not describe producing the titanium halide containing catalyst component by co-pulverizing the magnesium compound and an electron-donor compound and then subsequently reacting this with an organic phosphite and then reacting with a titanium halide.